JP3089771B2 - Dye thermal transfer image receiving sheet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dye thermal transfer image receiving sheet. More specifically, the present invention relates to a sheet for dyeing and receiving a full-color image by a sublimable disperse dye, and does not fuse with an ink sheet during printing, has excellent runnability, has high image density, is sharp, and The present invention relates to a dye thermal transfer image receiving sheet having excellent storage stability such as heat resistance.

[0002]

2. Description of the Related Art In recent years, the development of a thermal transfer type high-quality color hard copy, in particular, a dye thermal transfer type printer has been rapidly progressing. In a dye thermal transfer printer, the sublimation dye layers of three colors (yellow, magenta, and cyan) are heated by continuously controlling the heating energy of the thermal head, thereby changing the transfer amount of the dye of each color. Thus, it is possible to form a full-color image of density gradation.

In order to obtain a high-quality image on a dye thermal transfer image-receiving sheet, an image-receiving layer resin having a high transfer rate and a large amount of dye and having good storability has been studied. Conventionally,
Various polyester resins and PVC resins have been used as the dyeing resin having such a high transfer speed and dyeing amount and having excellent storage stability.

For example, JP-A-57-107885 discloses that
The disclosure of using a saturated polyester resin is disclosed in
No. 1-3796 discloses the use of a sulfonated phthalic acid-modified polyester resin. Further, JP-A-63
-7971 discloses the use of a polyester resin comprising a phenyl group-containing polyol and a dicarboxylic acid. Further, JP-A-59-223425, JP-A-6
JP-A-3-51181 and JP-A-2-67194 disclose the use of polyvinyl chloride resins. However, none of these was satisfactory enough.

As a dyeing mechanism of the dye transfer system, as described in "Coloring Material, 59 (10), 1986 p607",
An image receiving layer resin having a relatively low glass transition temperature,
When the resin is locally heated, the polymer chains in the amorphous region of the resin in that portion violently generate molecular motion, melt and soften, and become a highly viscous liquid. Next, the dye sublimated by the transfer operation jumps into this part, and when this part is cooled, the dye molecules are embedded in the amorphous region and dye the image receiving layer resin, forming a colored image. Is done.

[0006] Such a dye thermal transfer system has the disadvantage that a large amount of energy is required for sublimation of the dye and the transfer speed is slow. In order to improve the transfer speed, attempts have been made to lower the glass transition temperature of the image receiving layer used in the dye thermal transfer image receiving sheet. However, it has been known that this causes a problem that the surface of the image receiving layer is roughened by heating in the printing operation, and the gloss of the transferred image is reduced.
Also, during the printing operation, the image receiving layer is locally heated to a temperature of 200 ° C. or higher by heating with a thermal head or the like, so that the binder in the dye layer of the ink sheet and the thermoplastic resin in the image receiving layer are softened. Alternatively, there is a problem in that the ink sheet and the image receiving layer are fused and cannot be peeled off as a result.

Heretofore, as a method for preventing such thermal fusion between the ink sheet and the image receiving layer, as is well known in the fields of paints, fusion heat transfer ink sheets, and thermal papers, there have been known mold release. There is a method of adding an agent or a release agent.
In addition, as described in, for example, JP-A-57-107885, a method of adding a pigment to an image-receiving layer to roughen the surface is disclosed in JP-A-58-21597. A method using a crosslinkable resin as the resin for the image receiving layer, and a small amount of a release agent is blended into each of the ink sheet and the image receiving layer as described in JP-A-3-45389. Methods have been proposed.

However, although a method of adding a release agent or a release agent to the image receiving layer is effective for preventing thermal fusion with the ink sheet, after the printing, the release agent or the release agent is removed from the image receiving layer.
Alternatively, the release agent may be released, causing problems such as bleeding of the image during storage, or the dye forming the image may migrate to and contaminate other articles in contact with the image. Was. In addition, the method of roughening the image receiving layer by adding a pigment causes a problem that the adhesion between the ink sheet and the image receiving layer becomes insufficient and the uniformity of the image density is reduced. Further, a method using a crosslinkable resin is not preferable because curing of the resin proceeds due to crosslinking and dyeing properties of the dye become poor. Also, if this is heated to crosslink the image receiving layer, the image receiving sheet curls due to the difference in shrinkage on the front and back of the image receiving sheet, causing a problem in feeding and discharging to the printer. I was Further, the method using a release agent changes the friction coefficient of the surface of the image receiving sheet. In particular, in order to stabilize the traveling properties of the cut sheet, it is necessary that the friction between the front and back of the paper and the friction between the paper and the ribbon be controlled within an appropriate range. Conventional anti-fusing measures have often made the runnability of the resulting image receiving sheet unstable.

[0009]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned drawbacks of the prior art, and has high sensitivity and density of a dye image thermally transferred from an ink sheet, and has no thermal fusion with the ink sheet. Another object of the present invention is to provide a dye thermal transfer image receiving sheet having stable running properties.

[0010]

The dye thermal transfer image receiving sheet of the present invention receives a sheet-like support and a dye formed on at least one surface of the support and transferred from the ink sheet by heating. Having an image receiving layer,
Wherein the image receiving layer comprises: (1) a sublimation dye-receiving synthetic resin having a hydroxyl group, or a natural resin; (2) an isocyanate compound; and (3) a long-chain aliphatic hydrocarbon group containing 6 or more carbon atoms. And a reaction product with a long-chain aliphatic alcohol having a hydroxyl group bonded to at least one terminal thereof as a main component.

[0011]

The reason why the image receiving layer of the present invention is excellent in the property of preventing thermal fusion with an ink sheet is not sufficiently clear but is presumed as follows. In an image receiving layer formed by mixing a release agent such as silicone with a conventional dyeing resin, the compounded silicone or the like is oriented at the interface between the image receiving layer and air, so that the image receiving layer and the ink are Although fusion with the sheet was prevented, the silicone oriented at the interface was released from the image receiving layer together with the transferred dye, which caused image blurring and the like during storage of the recorded image. However, it is presumed that the image-receiving layer of the present invention weakens the adhesive force of the image-receiving layer due to the action and effect of the aliphatic compound component constituting the image-receiving layer resin, which prevents fusion with the ink sheet. . In addition, since the aliphatic compound component of the image-receiving layer resin is bonded to the resin main chain via the isocyanate, it is considered that bleeding of an image or the like can be prevented.

The hydroxyl-containing sublimation dye-receiving synthetic resin or natural resin used as a resin-forming component of the image-receiving layer of the present invention includes polyester resins, urethane resins, epoxy resins, polycarbonate resins, acetal resins, and the like. PVC resin, (meth) acrylic resin,
(Meth) acrylic ester resin, cellulose resin,
Rosin-based resins and the like can be mentioned. Further, a modified natural resin obtained by esterifying a cellulose resin or a rosin resin can be used.

As the isocyanate usable in the present invention, any conventionally known isocyanate compound can be used as it is. Specific examples thereof include diphenylmethane diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, phenylene diisocyanate, and tolylene diisocyanate.

The aliphatic compound having a hydroxyl group used in the present invention is selected from long-chain aliphatic alcohols having a hydroxyl group bonded to one end or both ends of a long-chain aliphatic hydrocarbon group. Specifically, carbon atoms such as decane alcohol, dodecane alcohol, hexadecane alcohol, eicosane alcohol, heneicosane alcohol, tetracosane alcohol, pentacosane alcohol, hexacosane alcohol, nonacosane alcohol, and triacontan alcohol, etc. The number is 6 or more, preferably 8
Up to 30 aliphatic alcohols are used. Further, it may be branched into a carbon atom chain, and may contain an ether bond or an ester bond between the cyclic structure and the long-chain aliphatic hydrocarbon group.

In the image receiving layer of the present invention, low molecular organic compounds such as substituted phenols and terpenes can be blended for the purpose of preventing oxidation, absorbing ultraviolet light, sensitizing and the like. In addition, white pigments generally used to improve the whiteness and opacity of paints, fluorescent dyes for adjusting the color tone of the image receiving layer, and dyes such as blue and violet can also be added to the image receiving layer as necessary. is there. It is convenient to mix the above-mentioned additives such as the white pigment, the ultraviolet absorber and the cross-linking agent with the resin of the image receiving layer which is a main component of the image receiving layer, and to apply the ultraviolet absorber to another coating. The layer may be coated on or under the image receiving layer.

In order to prevent static electricity from being generated when the image receiving sheet travels in the printer and to cause running trouble, an antistatic agent is added to at least one side of the sheet in the image receiving layer. Alternatively, it may be contained by a method such as disposing a back coat containing the same. As the antistatic agent, a cationic hydrophilic polymer is often used.

Examples of the sheet-like support used in the present invention include high-quality paper, coated paper, polyester film, and synthetic paper comprising a uniaxial or biaxially stretched film containing polyolefin and an inorganic pigment as main components, depending on the use. And a laminated sheet obtained by compounding them, and a laminated paper obtained by extruding and laminating a resin composition containing a polyolefin resin and a pigment as main components on a paper substrate. The thickness of the support used in the present invention is preferably from 20 to 250 μm, and the basis weight is preferably from 20 to 250 g / m ² .

Generally, the thickness of the image receiving layer is from 1 to 20 g / m
Preferably ^2, more preferably 4 to 10 g / m ^2. If the thickness of the image receiving layer is too thin, the density and sensitivity of the image decrease, and the uniformity of the image deteriorates due to the limitation of coating accuracy. On the other hand, if it is too thick, the effect of the obtained image receiving layer is saturated, which is not only uneconomical, but also lowers the strength of the image receiving layer.

[0019]

The present invention will be described in more detail with reference to the following examples, but the scope of the present invention is not limited thereby.

Embodiment 1

The dicarboxylic acid component and the diol component are heated in a nitrogen atmosphere together with a small amount of a catalyst composed of calcium acetate and antimony trioxide, heated to 150 ° C., and maintained at this temperature for 1 hour. Reacted.
This reaction system was further subjected to a polycondensation reaction at 250 ° C. for 3 hours while maintaining a vacuum of 0.1 mmHg or less, and at the same time, unreacted ethylene glycol was removed. Polyester resin-1 having a hydroxyl group was obtained.

Synthesis of Resin-1 for Image Receiving Layer One mole of the above-mentioned hydroxyl-containing polyester resin was mixed with 1 mole of isophorone diisocyanate, 2 moles of stearyl alcohol, and a mixed solvent of toluene / MEK as a diluent. Charge the reactor, gradually heat the reaction mixture with stirring, raise the temperature to 75 ° C,
For 2 hours. Further, a trace of stannous octylate was added to the reaction system as a urethanization catalyst, and the resulting mixture was 75-80.
C. for 5 hours to synthesize Resin-1 for an image receiving layer.

Preparation of Paint-1 for Image Receiving Layer Paint-1 having the following composition was prepared . Image receiving layer resin-1 100 parts by weight Toluene / MEK = 4/1 mixed solvent 400 parts by weight

Preparation of Dye Thermal Transfer Image Receiving Sheet A sheet of 150 g / m ² high-quality paper laminated with 30 μm of polyethylene on both sides was used as a sheet-like support. The above-mentioned paint-1 was applied on one surface of this sheet-like substrate as an image-receiving layer of a sublimable dye at a dry solid coating amount of 5 g / m ^2.
And dried to form an image receiving layer. A dye thermal transfer image receiving sheet was obtained.

On the image receiving sheet obtained as described above, a step pattern was printed by using a commercially available sublimation transfer color video printer (trade name: VP7100, manufactured by Fuji Film Co., Ltd.). The fusion with the ink sheet and the running property of the sheet were evaluated. The fusion resistance with the ink sheet and the running property of the sheet were evaluated on a five-point scale. Excellent: Grade 5, Good: Grade 4, General quality: Grade 3, Inferior: Grade 2, Grade with serious defects: Grade 1. Table 1 shows the evaluation results.

Example 2 The same operation as in Example 1 was performed. However, the coating for the image receiving layer was prepared as follows. 1 mol of isophorone diisocyanate and 1 mol of ethylene oxide adduct of cetyl alcohol were mixed with 1 mol of synthetic vinyl chloride / vinyl propionate copolymer (trade name: QN503, manufactured by Tosoh Corporation) of Resin-2 for image receiving layer , and further diluted. A mixed solution of toluene / MEK / ethyl acetate is mixed as an agent, and the obtained reaction mixture is charged into a reactor, and the mixture is heated gradually to 75 ° C. while stirring, and reacted at 75 to 80 ° C. for 2 hours. I let it. Further, traces of stannous octylate were added to this reaction system as a urethanization catalyst, and the mixture was reacted at 75 to 80 ° C. for 5 hours to obtain Resin-2 for an image receiving layer.

Preparation of Image Receiving Layer Coating-2 Resin for Image Receiving Layer-2 100 parts by weight Toluene / MEK / Ethyl acetate = 3/1/1 mixed solvent 400 parts by weight The evaluation results are shown in Table 1.

Example 3 The same operation as in Example 1 was performed. However, the paint for the image receiving layer was prepared as follows. Synthesis of Resin-3 for Image Receiving Layer 31.6 parts by weight of disproportionated rosin containing 52% by weight of dehydroabietic acid, 63.3 parts by weight of epichlorohydrone, and 0.03 part by weight of benzyltrimethylammonium chloride. Was charged into a reaction vessel, and the reaction mixture was dissolved under stirring, then heated to 80 ° C., and reacted at the same temperature for 4 hours. Further, the reaction system was charged with granular sodium hydroxide 5.
07 parts by weight, filtered off at 100 ° C. under stirring,
Rosin glycidyl ester was obtained. This rosin glycidyl ester, isophthalic acid monoester, and benzyltrimethylammonium chloride as an esterification catalyst are charged into a reactor, and heated to 105 to 110 ° C. under a nitrogen stream.
The reaction was completed over 6 hours to obtain a modified natural resin-3 having a hydroxyl group. In 1 mol of the modified natural resin-3,
1 mole of isophorone diisocyanate, 2 moles of stearyl alcohol and toluene / MEK as diluent
The mixed solution was added and charged into a reactor, and the reaction mixture was gradually heated while stirring, and the temperature was raised to 75 ° C.
The reaction was carried out at 〜80 ° C. for 2 hours. Further, a trace of stannous octoate is added to the reaction system as a urethanization catalyst,
The reaction was carried out at 75 to 80 ° C. for 5 hours to prepare Resin-3 for an image receiving layer.

Preparation of Paint 3 for Image Receiving Layer 100 parts by weight of image receiving layer resin 3 400 parts by weight of toluene / MEK / ethyl acetate = 3/1/1 solution The evaluation results are shown in Table 1.

Comparative Example 1 The same operation as in Example 1 was performed. However, a paint having the following composition was used as the coating for the image receiving layer. Preparation of Image Receiving Layer Coating-4 Polyester Resin Having a Hydroxyl Group- 1 100 parts by weight 400 parts by weight of toluene / MEK = 4/1 solution The evaluation results are shown in Table 1.

Comparative Example 2 The same operation as in Example 1 was performed. However, a paint having the following composition was used as the coating for the image receiving layer. Preparation of Image Receiving Layer Coating-5 Vinyl chloride / vinyl propionate (trademark: QN503, manufactured by Tosoh Corporation) 100 parts by weight Toluene / MEK = 4/1 solution 400 parts by weight Evaluation results are shown in Table 1.

Comparative Example 3 The same operation as in Example 1 was performed. However, a paint having the following composition was used as the coating for the image receiving layer. Preparation of Image Receiving Layer Coating-6 Modified Natural Resin-3 100 parts by weight Toluene / MEK = 4/1 solution 400 parts by weight The evaluation results are shown in Table 1.

Comparative Example 4 The same operation as in Example 1 was performed. However, a paint having the following composition was used as the coating for the image receiving layer. Preparation of paint 7 for image receiving layer Polyester resin having a hydroxyl group-1 100 parts by weight Isocyanate (trade name: Coronate EH, manufactured by Nippon Polyurethane Co.) 10 parts by weight Stearyl alcohol 5 parts by weight Toluene / MEK = 4/1 solution 400 parts by weight Evaluation Table 1 shows the results.

[0034]

[Table 1]

[0035]

The heat transfer image receiving sheet according to the present invention comprises:
An image receiving layer for receiving and fixing a sublimation dye image, (1) a sublimation dye-receiving synthetic resin having a hydroxyl group, or a natural resin,
(2) by using an isocyanate compound and (3) a reaction product of an aliphatic alcohol having at least one terminal hydroxyl group and having at least one terminal hydroxyl group,
It has succeeded in improving the sensitivity and density of a dye image, preventing thermal fusion with an ink sheet, and stabilizing the running property.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-224794 (JP, A) JP-A-61-132387 (JP, A) JP-A-63-221091 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) B41M 5/38-5/40

Claims (1)

(57) [Claims] 1. A sheet-like support, comprising: an image receiving layer formed on at least one surface of the support and receiving a dye transferred from an ink sheet by heating, wherein the image receiving layer comprises: (1) a sublimation dye-accepting synthetic resin having a hydroxyl group, or a natural resin; (2) an isocyanate compound; (3) a long-chain aliphatic hydrocarbon group containing 6 or more carbon atoms; A dye thermal transfer image receiving sheet containing, as a main component, a reaction product with a long-chain aliphatic alcohol having a hydroxyl group bonded to a terminal.